Organopolysiloxane and method for the preparation of the same

Abstract

A radiation-curable coating composition is formulated from a silicone resin that includes acrylate or methacrylate functional organic groups and phenyl groups.

What is claimed is: 
     
       1. A composition comprising an organopolysiloxane having an average unit formula   (R.sup.1 SiO.sub.3/2).sub.a (R.sup.2 R.sup.3 SiO.sub.2/2).sub.b (SiO.sub.4/2).sub.c                                       (I)     wherein R 1 , R 2 , and R 3  denote organic groups selected from the group consisting of monovalent hydrocarbon groups, organic groups of the following general formula that contain acryloyl groups or methacryloyl groups ##STR8## wherein R 4  denotes a divalent organic group, each R 5  independently denotes hydrogen or a monovalent organic group, and each R 6  denotes an acryloyl group or methacryloyl group or hydrogen atom and at least 1 of R 6  is an acryloyl group or methacryloyl group, organic groups with the following general formula that contain the acryloyl group or methacryloyl group ##STR9## wherein R 4  and R 6  are defined as above, and epoxy-functional organic groups, wherein 5 to 30 mole % of said organic groups of formula (I) are groups that contain acryloyl or methacryloyl groups, 5 to 90 mole % of said organic groups of formula (I) are phenyl groups, 0.5 to 3 mole % of said organic groups are epoxy-functional organic groups and a is a positive number, b is zero or a positive number, c is zero or a positive number, b/a is zero to 2, and c/(a+b+c) is zero to 0.3.   
     
     
       2. A composition in accordance with claim 1 further comprising a photoinitiator. 
     
     
       3. A method for the preparation of an organopolysiloxane of the general formula (I) of claim 1, said method comprising reacting (A) an epoxy-functional organopolysiloxane having the general formula   (R.sup.7 SiO.sub.3/2).sub.d (R.sup.8 R.sup.9 SiO.sub.2/2).sub.e (SiO.sub.4/2).sub.f       wherein R 7 , R 8 , and R 9  denote organic groups selected from the group consisting of monovalent hydrocarbon groups and epoxy-functional organic groups, and said epoxy-functional organic groups are 5 to 30 mole % of said organic groups, 5 to 90 mole % of said organic groups are phenyl groups, d is a positive number, e is zero or a positive number, f is zero or a positive number, e/d is zero to 2, and f/(d+e+f) is zero to 0.3) with     (B) a sufficient quantity of acrylic acid or methacrylic acid to cause 0.3 to 0.9 moles of acrylic acid or methacrylic acid to react with each mole of epoxy groups in component (A).   
     
     
       4. A method in accordance with claim 3 further comprising co-reacting about 0.5 mole of an anhydride or acid halide of acrylic acid or methacrylic acid for each mole of epoxy groups in component (A) during the reaction of components (A) and (B). 
     
     
       5. An article of manufacture comprising a substrate presenting at least one surface and said surface having a cured coating formed thereon, said cured coating being formed from the composition of claim 1.